ABSTRACT
In 1966, Andreas Rett, an Austrian pediatrician in Vienna, first described a peculiar disorder in girls characterized by global deceleration of psychomotor development and subsequent loss of acquired cognitive and motor skills, occurring after 6-18 months of apparently normal development. In 1984, a panel of international experts developed diagnostic criteria for Rett syndrome (RS). Diagnostic criteria have been separated into three categories: necessary criteria, supportive criteria, and exclusion criteria. A child neurologist may wish to look further to exclude congenital metabolic defects and possible brain injury from anoxia, ischemia, or trauma. Neuroimaging may also be required, including magnetic resonance imaging, with volumetric studies, single photon emission computed tomography, cerebral proton magnetic resonance spectroscopy, and positron emission tomography. The earliest hypothesis on the inheritance of RS was founded on the seemingly exclusive appearance of the disorder in females. Most of the cases of RS are isolated, apart from some cases of affected identical twins.
